A traction battery of a vehicle such as a hybrid electric vehicle (HEV) or a battery-only electric vehicle (BEV) produces heat when releasing and storing electric energy. Thermal management of the battery may improve battery performance and extend battery life.
Air from the vehicle cabin can be used to cool the battery. Typically, a fan is operated to cause air from the cabin to enter an intake passage to the battery, flow across the battery, and exit an exhaust passage from the battery. Blockage of air flow (i.e., reduced or no air flow) can be caused by a passage being blocked or obstructed and/or by the fan having a damaged fan blade or the like. Any of these situations may cause the air flow to be reduced or absent even though the fan is spinning as commanded such that a proper amount of air flow would normally be present.